My aforementioned patent application includes an overview of subsoil dewatering as a method of enhancing and stabilizing beaches subject to erosion by the action of waves, tides, or other currents.
Under normal conditions, nature's transport of non-cohesive subsoil (such as sand) periodically to and onto a beach and off or away from the beach is at--or close to--equilibrium (zero net transport). whereupon little or no cumulative change in beach extent is noticed. Seasonal or other variations may tend to remove sand (erosion by negative net transport) or to replace it (accretion by positive net transport) for substantial periods of time but often average out over a few years if not during each individual year. However, some undergo consistent beach accretion or beach loss for many years. Beach accretion is hardly ever a cause for concern, but continuing or repeated beach erosion occasions financial and esthetic losses, greatly disturbing landowners, municipalities, tourists, etc.
As detailed in my mentioned patent, dewatering of the beachface at a level just below mean low water is beneficial by removing part of the overlying water in which non-cohesive subsoil is suspended, thereby increasing the concentration of suspended subsoil in the suspending water, whereupon a bit more of such subsoil than usual is deposited on the beachface during wave onrush and a bit less than usual is removed during the ensuing backwash. Such dewatering need not be continuous but only sufficiently often to assure that on the average the beach receives as much sand as it loses.
Some of the worst beach erosion occurs suddenly, during storms in which great expanses of beach are carried away, The disruptive effect of storms may be ameliorated somewhat by building a beach outward during normal times to provide a buffer or sacrificial zone. Retention of excess sand on the beach so as to appease nature's appetite when on a rampage is generally prudent and much better than periodically dredging up sand and depositing it onto the beach, only to be carried off in a few months. Whether the most violent storms can be neutralized is doubtful, but the present invention not only extends my previous invention to enhance day-to-day net accretion but also modifies its means and methods to reduce storm loss.